(Reuters) - Long-hitting Dustin Johnson could not maintain his overnight lead at the Crowne Plaza Invitational as he followed his strong start with an average second round in Fort Worth, Texas on Friday.

American Johnson, who had opened with a five-under-par 65 on Thursday to head the field by a stroke, could manage only a 70 in fine morning conditions at the iconic Colonial Country Club.

The world number 14 mixed three birdies with three bogeys to finish two shots behind early pacesetter and PGA Tour rookie Brice Garnett, who carded a 66 for a seven-under total of 133.

Garnett, 101st on the tour points list, made a rousing start with an eagle at the par-five first, where he rolled in a 17-footer.

He led fellow Americans Chris Stroud (64) and Robert Streb (68) by one stroke with half the field back in the clubhouse.

Brendon Todd, who clinched his first PGA Tour victory at the Byron Nelson Championship in nearby Irving on Sunday, trailed by five shots after consecutive rounds of 69.

Newly anointed world number one Adam Scott had a late tee time on Friday. The Australian had opened with a one-over 71.

The Crowne Plaza Invitational is one of the older events on the PGA Tour and has been held since 1946 at its permanent home of Colonial Country Club, popularly known as Hogan’s Alley.

Golfing great and former Fort Worth resident Ben Hogan won at the venue five times, including the first two years of the tournament.

Reporting by Andrew Both in Cary, North Carolina; Editing by Mark Lamport-Stokes